From reference lists of the participating elastomer EPDM producers SKZ selected 39 roofing projects in Germany, Austria, the Netherlands and Sweden, from late 90's ranging in age and installed between 1968 and 1996. From the samples taken the mechanical properties were determined, such as hardness, tensile strength and elongation at break. On all roofs that were investigated the EPDM roofing materials fulfils its function as waterproof membranes completely. The samples visually showed no serious ageing. The final outcome based on the service life for Hertalan EPDM roofing was >50 years.